Input/output device

Updated: 08/16/2021 by Computer Hope
USB flash drive

Alternatively called an IO device, an input/output device is any hardware used by a human operator or other systems to communicate with a computer. As the name suggests, input/output devices are capable of sending data (output) to a computer and receiving data from a computer (input).

Examples of input/output devices


See our input device and output device definitions for a list of each type of device.


Drives such as a CD-ROM, DVD, floppy diskette drive, hard drive, and USB flash drive are more commonly known as storage devices.

What are the input/output devices of my computer?

All computers have a hard drive, as they could not function without it. Today, most computers have a CD-RW or DVD-RW drive, network card, and a sound card (or onboard sound on the motherboard), which are all input/output devices. Some people consider a sound card to be more of an output device, but it does have input capabilities as well. A microphone can connect to a computer through the sound card, allowing the sound card to accept sound (input) and send it to the computer.

If you save files to access on other computers or want to copy files from one computer to another, use a USB flash drive.

Older computers used to have a floppy diskette drive and a modem, but both are seldomly used anymore and not found on most computers today.

Why does a computer need an input/output device?

Without an input-output device, computers would not be able to access data and save data. A computer's operating system, like Windows or macOS, is stored on a hard drive and accessed by the computer. Without the hard drive, a computer could not access an operating system and could not function.

To access the Internet, a computer needs to use an input/output device, like a modem or network card. Without either of those, the computer could not connect to or access the Internet.

What are I/O device errors?

Because most hardware devices do not require input and output communication with the computer, most IO devices are storage devices. So, when you encounter an I/O error or I/O device error, it's an indication that the operating system cannot read or write to a device.

Reasons why you may get an IO device error

  • Write protection is enabled. For example, if write-protection on an SD card.
  • Trying to write to a disc that is not writable. For example, trying to burn to a CD and not a CD-R disc.
  • No more disk space.
  • The file is used by another user or computer program.
  • Not enough rights or permissions to read or write.
  • No physical or virtual connection.
  • Bad or missing drivers preventing the drive from being accessed.
  • Failing or bad hardware.

What can fix I/O errors?

Depending on what device is giving you the I/O error can change how to troubleshoot these errors. If you are not certain what device is giving you the error, follow the general troubleshooting steps. Otherwise, try following the specific steps for the device giving you the error.

IO error

General troubleshooting for I/O errors

  1. Reboot the computer.
  2. Make sure you have all of the latest drivers for your devices.
  3. If you are using Microsoft Windows, make sure there are no errors in Device Manager.
  4. If you have recently moved the computer, open the computer and make sure the cables inside the computer are firmly connected.

Troubleshooting I/O errors with removable media

With removable media such as a floppy diskette, CDs, or SD cards, I/O errors may be occurring because the removable media you are using has failed. The best way to quickly determine if this is the cause is to try an alternative. For example, if you are getting an I/O error with a disc, try another disc in the computer to see if you get the same error. If the same error occurs, then you have a problem with the drive. If you can read another disc with no errors, then it may be a bad or dirty disc.

If you're using removable media such as a floppy diskette or SD card, make sure it is not write-protected.

If you are trying to burn (write) information to a CD-R disc, make sure you are using a new disc. If the disc was closed, you cannot write any more information to that disc.

Troubleshooting I/O errors occurring when accessing a network file

Any I/O error encountered when trying to read or write a file over the network is caused by either a permission error or a connection issue. Make sure your connection works by trying to read/write another file in a different location. If the connection looks good, then it's likely you either lack the proper rights or the file is in use and is locked.

CPU, Device, Hardware terms, Input, Keyboard, Output